2015 – Internal Meta documents estimate more than 4 million Instagram users are under 13, representing roughly 30 % of U.S. 10‑12‑year‑olds, and reveal that the platform lacks robust age‑verification mechanisms[3].

2018 – Meta rolls out Instagram’s daily‑limit tool and launches Messenger Kids, but internal data later show only about 1.1 % of teen users adopt the limit feature[2].

2019 – Executives exchange emails that discuss “tween” retention strategies, criticize unenforced age limits, and set informal goals to increase time spent on Instagram, indicating early awareness of under‑13 usage[2].

Dec 2019 – Instagram begins requiring new users to enter a birthdate at sign‑up, a policy that later expands to existing accounts in August 2021, meaning early adopters like Kaley join without age checks[3].

Aug 2021 – Instagram extends birth‑date verification to legacy accounts, yet internal estimates still show millions of under‑13 users remain active[3].

2022 – Internal targets project average daily Instagram use to rise from 40 minutes in 2023 to 46 minutes in 2026, reflecting a “stretch goal” to outpace TikTok[3].

2024 – Parents gather outside the Los Angeles courthouse during a related hearing, recalling Zuckerberg’s congressional apology for Instagram’s impact on teen mental health and urging stronger safeguards[3].

2025 – Kaley’s deposition contains statements that later appear inconsistent with her trial testimony, which Meta’s lawyers cite to question the addiction diagnosis[6].

Early 2026 – TikTok and Snap settle similar youth‑addiction lawsuits with undisclosed terms, clearing the way for a focused bellwether trial against Meta and YouTube[2].

Feb 18, 2026 – Mark Zuckerberg testifies before a Los Angeles jury, admits regret that age‑verification tools arrived late, and acknowledges internal awareness of 4 million under‑13 users in 2015[10].

Feb 19, 2026 – Zuckerberg gives more than five hours of testimony, denies a causal link between Instagram and mental‑health harm, and asserts that Meta has shifted from time‑spending goals to a “utility‑focused” product strategy[2][7].

Feb 21, 2026 – The landmark social‑media addiction trial officially opens in federal court, accusing Meta and YouTube of engineering addictive experiences for minors and joining dozens of parallel lawsuits nationwide[9].

Feb 26, 2026 – Kaley files a federal lawsuit in Los Angeles against Meta and Google, alleging that Instagram and YouTube dominated her childhood, caused anxiety, depression, body‑dysmorphia and self‑harm, and that the case could set a precedent for youth‑online liability[1].

Feb 26‑27, 2026 – Kaley testifies that she used YouTube from age 6 and Instagram from age 9, bought likes, relied on beauty filters, and experienced a “rush” from notifications, while her former therapist links her mood swings to platform use[6][8][11].

Late Mar 2026 – The trial is slated to conclude by mid‑ to late‑March, with the verdict expected to influence thousands of pending social‑media addiction suits across the United States[1][10].

Summer 2026 – Two additional Los Angeles bellwether trials are scheduled, each poised to further shape national jurisprudence on platform liability[5].

2024‑present – Australia bans users under 16 from major social platforms, and the UK, Denmark, France and Spain consider similar age‑restriction legislation, reflecting a global push to curb teen exposure to addictive design[2].

Ongoing – A separate New Mexico state case proceeds against Meta, alleging its algorithms facilitate sexual exploitation of minors, and its outcome may affect other state‑level actions[5].